This is very interesting, I haven’t touched macOS development for quite a while but it’s good to know that libraries are still being written for both AppKit and SwiftUI on macOS.

I do feel that this library would benefit from an explanation on why this was needed. AFAIR AppKit already provides a native tabbing API where you can “just” (that “just” is doing a lot of heavy lifting) implement a few delegate methods and you get tabbing behavior for free, especially on document-based apps. (Sorry, I do not remember the specifics, it might have been a tad more difficult)

I’m not updated on the SwiftUI equivalent, but I would imagine that a similar API would exist much alike API for multiple windows or multiple documents.

I think everyone would benefit from a “why” explanation (which I definitely think would exist, since I’ve used too many AppKit APIs in pain), and also some screenshots for a demo app (so that we can expect how it would look and how much the look and feel would deviate from the native counterparts).

The website already has a demonstration of what this does that native tabs don’t do and how they look.

Native tabs work at the window level.